Crystallization in quasi-two-dimensional colloidal systems at an air-water interface

The crystallization of colloidal particles at an air-water interface is investigated by computer simulations. We numerically clarify the bond-orientational order parameter ${\Phi }_6$ with different particle concentrations. In addition, the profiles of the pair-correlation function $g\left(r\right),$ the orientational correlation function $g_B\mathrm{}\left(r\right),$ and the static structure factor $S\left(\mathbf{q}\right)$ of this system are calculated. We find the two-stage melting of the colloidal crystal and the existence of the hexatic phase at intermediate concentration.